sedimentary

Fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

AI-generated identification · may be incorrect

Gray-beige, dull to weakly earthy luster, fine-to-medium grained, and irregularly fractured; visible shell or skeletal fragments suggest a bioclastic texture. Calcite is Mohs hardness 3, has perfect rhombohedral cleavage, and reacts vigorously with dilute hydrochloric acid; specific gravity is about 2.7.

Identified September 8, 2026More sedimentary →

Explore Fossiliferous limestone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed when marine shells, carbonate mud, and skeletal debris accumulated on a shallow seafloor and lithified, commonly during the Paleozoic–Cenozoic. The exact age cannot be determined from the photograph alone.

Uses & applications

Used as crushed aggregate, cement and lime feedstock, building or ornamental stone, and as a fossil-collecting specimen; value is usually mainly educational or decorative.

Geological facts

The irregular cavities and pale fossil-like fragments are consistent with dissolved or partially preserved shells, bryozoans, or crinoid debris, though the image is insufficient for precise fossil identification.

Field identification & locations

Look for abundant carbonate fragments, gray-tan coloring, and acid effervescence; a steel nail usually will not scratch fresh calcite-rich surfaces, while a knife may. Common worldwide in marine sedimentary basins.